Underwater drilling method



ug- 27, 1968 c. E. wAKEFu-zmtn, 1R 3,398,790

UNDERWATER DR ILL ING METHOD Filed May 7, 1965 4 Sheets-Sheet l MG f INVENTOR www@ 4 Sheets-Sheet 2 C. E. WAKEFIELD, JR

UNDERWATER DRILLING METHOD Aug. 27, 1968 Filed May 7, .w65

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Aug 27, 1968 c. E. WAKEFIELD, 1R 3,398,790

UNDERWATER DRILLING METHOD Filed May '7, 1965 4 Sheets-Sheet .'3

INVENTOR. CA/Aaf 5 M4K/505@ J@ Y/uag 4 T MPA/EK Aug- 27, 1968 c. E. WAKEFIELD, JR 3,398,790

UNDERWATER DRILLING METHOD 4 Sheets-Sheet 4 Filed May 7, 1955 IIIII.. Ilul lill ATTIP/VEX United States Patent O 3,398,790 UNDERWATER DRILLING METHOD Charles E. Wakefield, Jr., Long Beach, Calif., assignor to Atlantic Richfield Company, a corporation of Pennsylvania Filed May 7, 1965, Ser. No. 454,019 4 Claims. (Cl. 166-.S)

ABSTRACT F THE DISCLOSURE Method for landing a casing pipe in an underwater drilling apparatus which comprises landing a conductor pipe, a conductor mandrel and a `riser in a well, then drilling out below the conductor pipe and lowering a surface casing through the riser and conductor mandrel and landing a shoulder on the surface casing on a mating shoulder portion within the conductor mandrel. If desired the surface casing can contain inwardly projecting shoulder portions therein for landing lfurther casings therein.

My present invention relates to offshore ldrilling and, more particularly, relates to an improved method for landing a casing pipe in an underwater drilling apparatus.

It has heretofore been a practice in offshore drilling operations to land a conductor pipe in a well and subsequently or concurrently lower to the well a condu-ctor mandrel which is or has been affixed to the top of the conductor pipe. The conductor pipe with conductor or drilling mandrel attached thereto may also be landed with a drilling 'base either on a drill pipe or on a riser attached to a conductor mandrel which is attached to the top of the conductor pipe. The riser extends from the drilling structure on the surface of the water and serves to maintain direct contact with the conductor pipe and provide a return path for drilling fluids. After the conductor pipe and conductor mandrel are landed in the well, the well is ydeepened for the placement of a surface pipe or casing in the well and the surface pipe subsequently landed on top of the conductor mandrel. Landing the surface pipe on the conductor mandrel necessitates unlatching the riser from the conductor mandrel and reattaching the riser to the wellhead structure by latching onto the surface pipe mandrel after the surface pipe is landed. Thus, changing the riser latching mechanism from the conductor mandrel to the surface pipe mandrel requires bringing the riser up to the drilling structure While the surface casing is being landed and then running the riser back down to watch the riser to the top of the surface casing on the surface casing mandrel.

It is an object of the present invention to avoid the aforementioned round trip of the riser to the drilling structure to run the surface pipe into the well and land it on the conductor mandrel.

Other objects and a more complete understandin-g of my present invention may be had by reference to the following specification and the appended claims when taken in conjunction with the following drawings, wherein:

FIG. 1 shows, partially in section, a drilling head and landing lbase suspended from a drilling structure (not shown) while a well is being drilled to receive a conductor pipe;

FIG. 2 shows the apparatus of FIG. 1 with the conductor pipe and drilling base landed on the formation at the well opening;

FIG. 3 shows the manner in which the hole for the surface pipe is drilled;

FIGS. 4-6 show the landing of casings within the con- `ductor mandrel;

FIG. 7 shows a production head landed in the conductor mandrel with the drill pipe;

FIG. 8 shows the `blowout preventers and riser installed on the production mandrel.

Referring briefly to the drawings, a method is shown for drilling in a formation underlying a body of water from a drilling structure (not shown) located at the surface of said body of water, wherein a conductor pipe 10 with a conductor mandrel 12 affixed thereon is landed in a well 14 in a landing base 16 seated on the ocean floor 18. The landing base 16 may Ibe of the type shown and described in my Patent No. 3,143,172 issued Aug. 4, 1964. After the conductor pipe is landed, the well is deepened sufficiently to receive the surface casing, and surface casing 20, as shown in FIG. 4, is landed within the conductor mandrel 12 on a shoulder 22. Additional casin-gs 24 and 26 may be landed within the surface casing 20, as shown in FIGS. 5 and 6, and a production head 28 then landed within the conductor mandrel, which apparatus is described more fully in a copending application of C. C. Brown, Ser. No. 456,968, filed May 19, 1965.

Referring more particularly to FIG. 1, drilling apparatus including a conductor pipe 10 and a conductor mandrel 12 is supported from a drilling structure (not shown) on a casing .riser 30 which is latched to the conductor mandrel 12 by any conventional means, such as on a conductor mandrel shoulder 32 with a latch mechanism 34. The drilling apparatus may also -be provided with a ram type double gate blowout preventer 36 and one or more bag type blowout preventers 38 and a second latch mechanism 40 for attaching the riser to the blowout preventers, The landing base 16 may be supported on the drilling apparatus shown attached to the riser with the drilling apparatus suspended in the Water over the well 14, a's shown in FIG. 1, while the conductor hole is being drilled with a conventional bit 42 and hole opener 44. After the hole 14 is deepened sufliciently to receive the conductor 10, the drilling apparatus is lowered by lengthenin'g the riser 30` from the drilling structure so that the conductor 10 extends into the hole 14 and the drilling -base 16 rests on the ocean bottom 18, as shown in FIG. 2.

With the conductor pipe and the drilling base landed as shown in FIG. 2, a drill is again operated through the riser and the drilling structure and the hole 14 deepened sufficiently to receive the surface casing 20. This drilling operation is illustrated in FIG. 3. With the surface casing hole drilled, the surface casing 20 which has a landing mandrel 46 attached to the upper end thereof, is lowered into the conductor pipe 10 and landed on internal shoulder 22 of the conductor mandrel 12, as shown in FIG. 4. The surface casing mandrel 46 may be locked against upward movement within the conductor mandrel, for example, by locking dogs which are shown in more detail in my copending application, Ser. No. 432,160, filed Feb. 12, 1965, for Well Casing Han-ger and Method for Hanging Same now 4Patent No. 3,279,539 issued Oct. 18, 1966.

As shown in FIG. 5, an inner casing 24 may be lowered in the surface casing 20 and landed on a shoulder 48 inside the surface casing. A seal 50 may be provided between the inner casing 24 and the conductor mandrel 12. Likewise, an inner liner 26 may be hung within the liner 24 on an internal shoulder 54 in the inner casing, as shown in FIG. 6.

After the desired number of Casin-gs are hung within the conductor mandrel, a production head 28 is landed on the drilling apparatus, as shown in FIG. 7, with the aid of stinger 29 which serves to maintain contact with the well when the drill pipe is raised to the drilling structure. Such production head may be of the type shown and described in my Patent No. 3,279,536, or my Patent No.

3,295,000 obtained jointly with C. C. Brown. Production tubing (not shown) may be landed within production head 28, as for example, on a tubing hanger mandrel of the type disclosed in my aforementioned patents, and the tubing hanger mandrel is landed within the production head 28 on shoulder 5S. After said production tubing is landed within the production head 28, production ow lines 59 are operatively connected to the production tubing with tlow line connectors 60. The blowout preventers and riser can be latched onto the upper end of the production head 28, as shown in FIG. 8, for further work in the well.

It can thus be seen that by utilizing my present method of landing a surface casing within a `conductor mandrel, the casing riser need not be round tripped to permit running and landing the surface casing.

Although my present invention has been described with a certain degree of particularity in respect to a specific embodiment thereof, the scope of my invention should not be so limited, but should be afforded the full breadth of the appended claims.

I claim:

1. A method for drilling a well in a formation underlying a body of water from a drilling structure through a casing riser aixed to the well, consisting essentially of the steps:

(a) latching a blowout preventer to a drilling mandrel having a shoulder therein and aflixed to the upper end of a conductor pipe,

(b) latching said blowout preventer to the lower end of said riser to thereby effect a connection between said riser and said mandrel,

(c) landing said conductor pipe in said well by lowering said conductor pipe, drilling mandrel, and blowout preventer to said well with said riser,

(d) drilling said well sufficiently `deep to vreceive a surface casing,

(e) maintaining said casing riser operatively connected to said mandrel to maintain a passage therethrough,

(f) lowering said surface casing through said riser into said well, and

(g) landing a mating shoulder portion connected to said surface casing on said shoulder in said drilling mandrel.

2. A method for drilling a well in a formation underlying a body of water from a floating vessel using a conductor casing having a conductor mandrel affixed to the upper end thereof and using a casing riser latched to blowout prevention equipment releasably alixed to the upper portion of said conductor mandrel and extending between said formation and said vessel, comprising the steps of:

drilling a hole for the conductor casing while suspending said conductor casing from said vessel with said casing riser, lowering said conductor casing into said hole,

drilling said hole sufficiently deep to receive a surface casing,

lowering a surface casing with a surface casing mandrel attached to the upper end thereof from said vessel through said riser into said well while said riser is latched to said conductor mandrel, said surface casing mandrel having a shoulder thereon, and

landing said surface casing mandrel in said conductor mandrel on .a mating shoulder therein for cooperating with the shoulder on said surface casing mandrel.

3. A method for drilling a well formation underlying a body of water from a drilling structure through a casing riser aiiixed to the well, consisting essentially of the steps of:

(a) latching a blowout preventer to a drilling mandrel having a shoulder therein and affixed to the upper end of a conductor pipe,

(b) latching said blowout preventer to the lower end of said riser to thereby effect a connection between said riser and said mandrel,

(c) landing said conductor pipe in said well by lowering said conductor pipe, drilling mandrel, and blowout preventer to said well with said riser,

(d) `drilling said well suiliciently deep to receive a surface casing,

(e) maintaining said casing riser operatively connected to said mandrel to maintain a passage therethrough,

(f) lowering said surface casing through said riser to said well,

(g) landing a mating shoulder portion connected to said surface casing on said shoulder in said drilling mandrel,

(h) landing a production head on said drilling mandrel,

and

(i) landing production tubing in said production head.

4. The method of claim 3 including the step of operatively connecting said production tubing to production ow lines through flow line connectors on said production head.

References Cited UNITED STATES PATENTS 3,099,317 7/1963 Todd 166-.6 X 3,310,107 3/1967 Yancey 1966-.6 3,315,741 4/ 1967 Triplett 166.5 2,606,003 I8/ 1952 McNeil 175-7 2,906,500 9/1959 Knapp et al. 166-66.5 3,137,348 6/1964 Ahlstone et al. 175-7 X 3,163,220 12/1964 Haeber et al 175-7 X 3,177,703 4/ 1965 Waters et al 166-.6 X 3,186,499 6/ 1965 Bullard et al 166-.5 3,291,210 12/ 1966 Johnstone et al 166-.6

CHARLES E. OCONNELL, Primary Examiner.

RICHARD E. FAVREAU, Assistant Examiner. 

